1. Field of Invention
The present invention relates generally to a support and maneuvering device for tracking, aiming, and steering applications and, more particularly, to a support and maneuvering device for solar heliostat/collector steering applications.
2. Description of the Prior Art
Generally speaking, conventional solar heliostat/collector structures are relatively large, having mirror diameters in many instances of approximately three to ten meters. The mounting arrangement for supporting the heliostat mirror and the drive mechanism for steering or maneuvering the mirror is, thus, usually of considerable size and mass. For example, in order for the conventional bulkier heliostat structure to withstand overturning wind forces, a central pedestal for the drive mechanism and for the mirror normally comprises a massive metal post to avoid buckling and a massive concrete foundation to prevent uprooting or overturning.
In addition, maneuvering the heliostat mirror usually requires costly support shaft bearings and geared drive motors. The production and installation costs for these drives, pedestals and foundations represent a large portion of a total cost of central receiver solar power systems that utilize heliostats. Such costs are a substantial factor in determining a feasibility of maintaining such systems.
Recently, in an attempt to reduce the material, fabrication and maintenance costs of prior art heliostats and their allied structures, a heliostat mirror or reflector has been formed from a stretched membrane of polymeric or metallic materials. The reflector module usually includes a rim or frame to which a stretched membrane is attached. Unfortunately, since some types of stretched membranes are relatively delicate, it is often not feasible to join such membranes directly to a reflector support frame, the drive mechanism, or other support structure.
One known method of providing a support and drive capability for the prior art stretched-membrane heliostat mirror is through a support spider. The support spider is constructed of rods having first ends attached to the rim of the stretched membrane and opposite ends converging to a junction zone that connects to a drive and support arrangement. However, unfortunately, usually the connection of the support spider to the rim of the heliostat mirror and to the drive mechanism and support pedestal is an intricate arrangement that also requires the use of costly support shafts, bearings and geared drive motors.